阅读说明：本技术 一种探测单元、超宽带光探测器及探测方法 (Detection unit, ultra-wideband photodetector and detection method ) 是由 赵自然 王迎新 吴东 王楠林 吴炜东 牛营营 陈猛 于 2019-10-29 设计创作，主要内容包括：本文公布了一种探测单元、超宽带光探测器及探测方法,探测单元包括NbS<Sub>3</Sub>晶体片和两个电极,两个所述电极分别设置在所述NbS<Sub>3</Sub>晶体片的长度方向两端,且分别与所述NbS<Sub>3</Sub>晶体片形成欧姆接触。超宽带光探测器包括上述的探测单元,以及用于采集所述探测单元上电势差数据的探测电路,两个所述电极分别与所述探测电路电连接。其探测方法主要包括：固定探测器、照射探测器和采集探测电路数据。本文涉及一种探测单元、超宽带光探测器及探测方法,可克服探测带宽窄的问题,其探测的带宽能从紫外覆盖到太赫兹波段,具有超宽探测带宽,并且其还具有高速灵敏的优点。(A detection unit, an ultra-wideband photodetector and a detection method are disclosed, the detection unit comprises NbS 3 A crystal plate and two electrodes respectively arranged on the NbS 3 Two ends of the crystal plate in the length direction are respectively connected with the NbS 3 The crystalline sheet forms an ohmic contact. The ultra-wideband light detector comprises the detection unit and a detection circuit used for collecting potential difference data on the detection unit, and the two electrodes are respectively electrically connected with the detection circuit. The detection method mainly comprises the following steps: the device comprises a fixed detector, an irradiation detector and a collection detection circuit. A detection unit, ultra-wideband photodetector and detection method are provided, which can overcome the detection bandThe problem of width, its bandwidth of surveying can cover to the terahertz wave band from the ultraviolet, has super wide detection bandwidth to it still has high-speed sensitive advantage.)

1. A detection unit for ultra-wideband optical detection, comprising NbS₃A crystal plate and two electrodes respectively arranged on the NbS₃Two ends of the crystal plate in the length direction are respectively connected with the NbS₃The crystalline sheet forms an ohmic contact.

2. An ultra-wideband light detector comprising a detection unit as claimed in claim 1, and a detection circuit for collecting potential difference data on said detection unit, two of said electrodes being electrically connected to said detection circuit, respectively.

3. The ultra-wideband light detector of claim 2, comprising a substrate to support the detection unit, the detection unit being secured to the substrate.

4. The ultra-wideband photodetector of claim 3, wherein the two electrodes are two metal electrodes of the same material.

5. The ultra-wideband photodetector of claim 3, wherein the two electrodes are metal electrodes of two different materials.

6. The UWB photodetector of claim 3 wherein the detection unit further comprises a gate dielectric layer, a gate electrode, and an antenna, wherein the two electrodes are a source electrode and a drain electrode, and the gate dielectric layer is disposed on the NbS₃A crystal wafer and the upper surface of a heterojunction formed by two electrodes, wherein the gate electrode is arranged at the upper end of the gate dielectric layer and is positioned on the NbS₃And the antenna is respectively connected with the source electrode and the gate electrode.

7. The ultra-wideband photodetector of claim 6, wherein said antenna comprises a first antenna and a second antenna that are separate, said first antenna being connected to said source electrode and said second antenna being connected to said gate electrode.

8. The ultra-wideband photodetector of claim 6, wherein the material of the gate dielectric layer comprises SiO₂、Al₂O₃、HfO₂Or hexagonal boron nitride.

9. The ultra-wideband photodetector of claim 6, wherein the antenna is configured as a helical antenna, a bowtie antenna, or a log-periodic antenna.

10. An ultra-wideband photodetector as claimed in claim 4, 5 or 6, characterised in that both electrodes are laminar and are both fixedOn the upper surface of the substrate or the NbS₃The upper surface of the crystalline sheet.

11. The ultra-wideband photodetector of any one of claims 3 to 9, wherein the substrate is in the form of a sheet and the material comprises sapphire, Si/SiO₂Quartz, glass or mica.

12. The ultra-wideband photodetector of any one of claims 3 to 9, wherein there are a plurality of said detecting elements, and a plurality of said detecting elements are arranged in a linear array or an area array.

13. The ultra-wideband photodetector of any one of claims 2 to 9, wherein the detection circuit is an electrical measurement device for reading the potential difference.

14. The ultra-wideband photodetector of claim 12, wherein a plurality of the detecting units are disposed on a substrate and arranged in a linear array, the substrate comprises a first substrate and a second substrate disposed at an interval, two electrodes of any one of the detecting units are respectively fixed on the first substrate and the second substrate, and the NbS is disposed on the first substrate and the second substrate₃And two ends of the crystal wafer are in ohmic contact with the two electrodes respectively.

15. The ultra-wideband photodetector of claim 12, wherein there are a plurality of said substrates, a plurality of said substrates are disposed on the same plane, said substrates and detecting elements are in one-to-one correspondence, two of said electrodes of each of said detecting elements penetrate the corresponding substrate, and NbS of said detecting elements₃The crystal wafer is arranged on one side of the substrate, and two ends of the crystal wafer are in ohmic contact with the two electrodes.

16. The ultra-wideband photodetector of claim 15, wherein the electrode is rectangular in cross-section and faces away from the NbS at the substrate₃One side of the crystalline sheet forms a pin.

17. A method of detection by an ultra-wideband photodetector as claimed in claims 2 to 16, comprising:

fixing a detector, wherein the detector is fixed on the optical translation table;

an irradiation detector for controlling the light source to irradiate the detector so that the light spot generated by the light source falls on the NbS₃On a crystal plate;

and acquiring data of the detection circuit, and reading and recording the potential difference change data at two ends of the detection unit.

Technical Field

The invention relates to the technical field of detection, in particular to a detection unit, an ultra-wideband light detector and a detection method.

Background

The optical detector can convert an optical signal into an electrical signal, and further detect the optical power incident on the surface of the optical detector. The ultra-wideband photodetector can simultaneously detect electromagnetic wave radiation of different wave bands, such as ultraviolet, visible light, infrared and even terahertz waves, and has very important functions in a plurality of fields such as infrared imaging, remote sensing, environment monitoring, astronomical detection, spectral analysis and the like. However, due to the limitation of photosensitive materials, the current optical detector can only work in a specific waveband, the ultra-wide spectrum detection at the present stage is realized by integrating detection methods of different wavebands and ensuring that all parts work synchronously, and the biggest problem of the method is that the device structure is very complicated and is difficult to be applied to practice. Therefore, ultra-wideband optical detection from terahertz to ultraviolet by using a single device becomes a research hotspot at present.

Based on WSe, subject to the size of the material's own band gap₂(see Kim H S, Chauhan K R, Kim J, ethyl. Flexible variable amplitude oxide for branched band transparent photodectector [ J]Applied Physics Letters,2017,110(10):101907.), Bi single crystal (see Yao J D, Shao J M, YangG W.ultra-broad and high-responsiveness photodetectors base on biosmuthfilmat room temperature[J].Scientific Reports,2015,5:12320.)，MoS₂(see Xie Y, Zhang B, Wang S, et al. ultrabroadband MoS₂Photodetector with Spectral Response from445 to 2717nm[J]Advanced Materials,2017,29(17): 1605972) and black phosphorus (see Xie Y, Zhang B, Wang S, et al₂Photodetector with Spectral Responsefrom 445 to 2717nm[J]The detectors of Advanced Materials,2017,29(17): 1605972) can only realize broadband detection of ultraviolet to infrared bands mostly, and are difficult to cover terahertz bands. Graphene and topological insulators have a dirac cone energy band structure and are considered as pets for realizing ultra-wideband optical detection. Unfortunately, for graphene, the light absorption of single-layer graphene is only 2.3%, which makes the responsivity of graphene detector only a few mV/W (CN 107104167 a). For topological insulators, only the surface has a dirac cone structure, and the problem of low absorption is also faced. In addition, the zero band gap structure enables the light detection dark current based on graphene and a topological insulator to be large, and the signal-to-noise ratio of the device is seriously influenced. Despite the existence of Graphene heterojunction (see high selectivity, Gate-Tunable, from-Temperature Mid-isolated photon depletion site on Graphene-Bi)₂Se₃Heterostructure), topological insulator heterojunction (see Yao, j.; shao, j.; wang, y.; zhao, z.; yang, G.ultra-broad and hightresponse of the Bi₂Te₃-Si heterojunction and its applications a photoresist detector from temperature in research environment, nanoscale 2015,7,12535 and 12541), and graphene detectors with three-dimensional microtube structure (CN107394001A), which either require additional bias or introduce a relatively complicated fabrication process, both of which restrict the practical application of the device. In summary, an ultra-wide spectrum detector with a detection bandwidth covering from terahertz to ultraviolet needs to be further researched.

Disclosure of Invention

The embodiment of the invention provides a detection unit, an ultra-wideband light detector and a detection method, which can overcome the problem of narrow detection bandwidth, can cover the detection bandwidth from ultraviolet to terahertz wave band, has ultra-wide detection bandwidth, and also has the advantages of high speed and sensitivity.

In order to solve the technical problems, the following technical scheme is adopted:

a detection unit for ultra-wideband optical detection, comprising NbS₃A crystal plate and two electrodes respectively arranged on the NbS₃Two ends of the crystal plate in the length direction are respectively connected with the NbS₃The crystalline sheet forms an ohmic contact.

The ultra-wideband light detector comprises the detection unit and a detection circuit used for collecting potential difference data on the detection unit, and the two electrodes are electrically connected with the detection circuit respectively.

One possible design includes a base to support the detection unit, the detection unit being fixed on the base.

In one possible embodiment, two of the electrodes are made of two metal electrodes of the same material.

In one possible embodiment, the two electrodes are two metal electrodes made of different materials.

In one possible design, the detecting unit further includes a gate dielectric layer, a gate electrode, and an antenna, wherein the two electrodes are a source electrode and a drain electrode, and the gate dielectric layer is laid on the NbS₃A crystal wafer and the upper surface of a heterojunction formed by two electrodes, wherein the gate electrode is arranged at the upper end of the gate dielectric layer and is positioned on the NbS₃And the antenna is respectively connected with the source electrode and the gate electrode.

In one possible design, the antenna includes a first antenna and a second antenna that are separated from each other, the first antenna is connected to the source electrode, and the second antenna is connected to the gate electrode.

In one possible design, the material of the gate dielectric layer includes SiO₂、Al₂O₃、HfO₂Or hexagonal boron nitride.

In one possible design, the antenna is configured as a helical antenna, a bowtie antenna or a log-periodic antenna.

One kind of possibilityIn the design of (1), both electrodes are in the form of sheets and are fixed to the upper surface of the substrate or to the NbS₃The upper surface of the crystalline sheet.

In one possible design, the substrate is in the form of a thin sheet and the material comprises sapphire, Si/SiO₂Quartz, glass or mica.

In one possible design, the number of the detection units is multiple, and the multiple detection units are arranged in a linear array or an area array.

In one possible design, the detection circuit is an electrical measuring device for reading potential differences.

In one possible design, the plurality of detecting units are arranged on a substrate and arranged in a linear array, the substrate includes a first substrate and a second substrate arranged at intervals, two electrodes of any one of the detecting units are respectively fixed on the first substrate and the second substrate, and the NbS is arranged on the first substrate and the second substrate₃And two ends of the crystal wafer are in ohmic contact with the two electrodes respectively.

In one possible design, the number of the substrates is multiple, the multiple substrates are disposed on the same plane, the substrates correspond to the detecting units one by one, two electrodes of each detecting unit penetrate through the corresponding substrate, and NbS of the detecting unit₃The crystal wafer is arranged on one side of the substrate, and two ends of the crystal wafer are in ohmic contact with the two electrodes.

In one possible embodiment, the electrode has a rectangular cross-section and faces away from the NbS at the substrate₃One side of the crystalline sheet forms a pin.

The present disclosure also provides a detection method of the above-mentioned ultra-broadband photodetector, including:

fixing a detector, wherein the detector is fixed on the optical translation table;

an irradiation detector for controlling the light source to irradiate the detector so that the light spot generated by the light source falls on the NbS₃On a crystal plate;

and acquiring data of the detection circuit, and reading and recording the potential difference change data at two ends of the detection unit.

The embodiment of the invention has the following beneficial effects:

when the detector of the embodiment of the invention is irradiated by the light source, the detector contains NbS₃The detection unit of the crystal can generate temperature gradient, so that potential difference in direct proportion to light intensity is generated at two ends of the detection unit, and meanwhile, the potential difference is amplified and read out through the detection circuit, so that ultra-wideband light detection can be realized.

The detector of the embodiment of the invention has the advantages that the detection bandwidth can cover from ultraviolet to terahertz wave band, the detection bandwidth is ultra-wide, and the detector is high-speed and sensitive.

The detector provided by the embodiment of the invention is simple to prepare, low in cost and wide in prospect in practical application.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The invention is further described below with reference to the accompanying drawings:

FIG. 1 is a schematic view of a probe according to a first embodiment;

FIG. 2 is a simplified diagram of the probe connection according to the first embodiment;

FIG. 3 is a schematic view of a detector according to a second embodiment;

FIG. 4 is a schematic view of a probe according to a third embodiment;

FIG. 5 is a schematic diagram of a detecting unit according to a third embodiment;

FIG. 6 is a simplified diagram of the probe connection according to the third embodiment;

FIG. 7 is a schematic view of a detector according to a fourth embodiment;

FIG. 8 is a schematic diagram of a fifth embodiment of the detector.

Reference numerals: 1-NbS₃The device comprises a crystal wafer, a 2-source electrode, a 3-drain electrode, a 4-substrate, a 4-1-first substrate, a 4-2-second substrate, a 5-gate dielectric layer, a 6-gate electrode, a 7-first antenna, an 8-second antenna, a 9-metal wire, a 10-light and a 11-detection circuit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following description of the embodiments of the present invention is provided with reference to the accompanying drawings, and it should be noted that, in the case of conflict, the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other.

Please refer to fig. 1 and fig. 2, which are schematic views illustrating an ultra-wideband photodetector according to a first embodiment of the present invention. As shown in fig. 1 and 2, the detector comprises a detection unit comprising NbS and a detection circuit 11 for collecting data of the detection unit₃ A crystal plate 1 and electrodes respectively arranged on NbS₃The two ends of the crystal wafer 1 in the length direction form ohmic contact with the crystal wafer, and the two electrodes are electrically connected with the detection circuit 11 respectively. Therefore, the detector can convert the light irradiated on the detector into an electric signal, and the electric signal is read by the detection circuit 11, so that ultra-wideband light detection is realized.

First, NbS₃Crystal plate 1, made of NbS₃The crystals are formed in long-strip sheets. NbS₃Is a typical quasi-one-dimensional semiconductor material with rich physical properties such as Peierls phase transition and charge density wave. In recent years, low dimensional materials with unique physical properties have become a focus of research, which also opens up the field of research for new ultra-wideband detection methods. At present, terahertz detection research based on low-dimensional materials mostly focuses on two-dimensional materials such as graphene and black phosphorus. In addition to these materials, there are many quasi-one-dimensional materials to be explored, such as NbS described above₃. However, currently for NbS₃The research on the terahertz wave is mostly focused on the crystal structure, the energy band structure and the charge density wave phase change characteristic, and few researches on a photoelectric detection method and even a terahertz detection method are carried out.

As shown in fig. 1 and 2, the two electrodes are two metal electrodes made of the same material and respectively provided with an active electrode 2 and a drain electrode 3, wherein the source electrode 2 and the drain electrode 3 are both in the form of thin plates and respectively provided on NbS₃Upper surface of the crystal plate 1 and NbS₃The crystalline plate 1 forms a good ohmic contact. Thus, the NbS₃The crystal plate 1 and two electrodes are fixed to form NbS₃-a heterojunction of metal ". Meanwhile, the source electrode 2 and the drain electrode 3 are electrically connected to the detection circuit 11 through leads (not shown), respectively, to form a loop so as to connect NbS to each other₃The electrical signal generated by the crystal plate 1 is transmitted to the detection circuit 11 for its measurement.

In addition, the detector comprises a substrate 4 for supporting the detecting unit, the substrate 4 is in the shape of a thin plate, and the NbS is₃The crystal plate 1 is fixed on the upper end surface of a substrate 4, the substrate 4 can provide stable mechanical support for the detector, and the material of the substrate includes but is not limited to sapphire, Si/SiO₂Quartz, glass or mica, in this example sapphire.

Therefore, the detector is simple to manufacture and relatively low in cost. And the detection method is simple and quick. Specifically, the detection method mainly comprises the following steps: fixed detector, illumination detector and acquisition detection circuit 11 data. During detection, the substrate of the detector needs to be fixed on a stable and reliable optical translation table, so that the substrate can face the light. Next, the light source is turned on so that its rays 10 can be focused on "NbS" through the optical path₃Heterojunction of-metal ", i.e. the light spot falls on NbS₃On the crystal plate 1, the diameter value of the light spot is smaller than NbS₃The length of the crystal plate 1 is 1-2mm, usually the size of the light spot in the laboratory is selected to be 1-2mm, so that the light spot can only fall on NbS₃One part of the wafer 1, which cannot cover the entire NbS₃A crystalline plate 1. At this time, under illumination, NbS₃The temperature of the crystal material rises to generate the photo-thermoelectric effect, so that obvious current is generated within a few milliseconds, the current intensity depends on the power of electromagnetic waves, and the photocurrent in a loop linearly increases along with the increase of the power of the electromagnetic waves; it is also understood that the light exposure causes a temperature difference across the detection unit, which temperature difference causes a potential difference across it that is proportional to the light intensity. Finally, the potential difference can be amplified and read out through the detection circuit 11, and ultra-wideband optical detection can be achieved. Therefore, the detection response is less than 10 milliseconds, the response is quick, the response is sensitive, meanwhile, the ultra-wide detection bandwidth is achieved, the band from ultraviolet to terahertz can be covered, and the application is wide.

Please refer to fig. 3, which is a diagram illustrating an ultra-wideband optical detector according to a second embodiment of the present invention. The detector comprises a detection unit and a detection circuit for collecting data of the detection unit, wherein the detection unit comprises NbS₃Crystal wafer 1 and electrode, compared with the detector of the first embodiment, the two electrodes of the first embodiment are two metal electrodes with different materials, i.e. the source electrode 2 and the drain electrode 3 have different materials, so that the detection unit forms two different "NbS" electrodes₃-a heterojunction of metal ". In addition, a coupling antenna can be adopted at the electrode to improve the absorption.

Therefore, the detector should select a light spot with a size much larger than that of the NbS during the detection process₃The length of the crystal wafer 1 enables light to irradiate the whole detection unit, and the Fermi energy levels at two ends of the detection unit are different due to different materials of metal electrodes at the two ends, so that Seebeck coefficients at the two ends are different. The photoelectric effect is generated under illumination, the photoelectric effect can generate obvious current within a few milliseconds, the current intensity depends on the power of electromagnetic waves, the photocurrent in a loop is linearly increased along with the increase of the power of the electromagnetic waves, and the data can be read out through a detection circuit to realize ultra-wideband optical detection.

Please refer to fig. 4 to fig. 6, which are schematic views of an ultra-wideband photodetector according to a third embodiment of the present invention. Compared with the detector of the first embodiment, the detection unit further comprises a gate dielectric layer 5, a gate electrode 6 and an antenna, wherein the two electrodes are a source electrode 2 and a drain electrode 3.

Specifically, the cap gate dielectric layer 5 is laid on the NbS₃The upper surface of the heterojunction formed by the crystal plate 1 and the two electrodes, and the gate dielectric layer 5 include but are not limited to SiO₂、Al₂O₃、HfO₂Or hexagonal boron nitride, the gate dielectric layer 5 of this embodiment is made of SiO₂. As far as the gate electrode 6 is concerned, it is also in the form of a thin plate, which is deposited on top of the gate dielectric 5 and is situated at NbS₃In the center of the crystal plate 1, the gate electrode 6 can gate the detection unit through the gate dielectric layer. In addition, both the source electrode 2 and the gate electrode 6 are provided with antennas, which in turn comprise a first antenna 7 arranged on the source electrode 2 and a second antenna 7 arranged on the gate electrodeThe second antenna 8, the first antenna 7 and the second antenna 8 on the antenna 6 are all metal pieces, and the metal pieces and the butterfly antenna are formed by the two antennas and can be coupled under the condition of power-on. The antenna is not limited to the bowtie antenna, but may be a helical antenna or a log periodic antenna. Meanwhile, the drain electrode 3 is connected to the detection circuit 11 through the metal wire 9, and the source electrode 2 is also connected to the detection circuit 11 to form a loop.

In the detection process of the detector, the size of the selected light spot is far larger than that of the NbS₃The length of the crystal plate 1 is such that the light impinges on the entire detection unit, and under light conditions, due to antenna coupling, the channel material (i.e. NbS) between the source electrode 2 and the gate electrode 6₃Crystal) absorbs more energy, the temperature is higher than the temperature of the material between the gate electrode 6 and the drain electrode 3, so that the photothermal effect is generated, a significant current is generated within a period of a few milliseconds, the current intensity depends on the power of electromagnetic waves, the photocurrent in a loop is linearly increased along with the increase of the power of the electromagnetic waves, and the detection circuit 11 can read data to realize ultra-wideband optical detection.

Referring to fig. 7, in an ultra-wideband optical detector according to a fourth embodiment of the present invention, compared to the detector according to the first embodiment, a plurality of detecting units are disposed on a substrate 4, and the plurality of detecting units are arranged in a linear array or an area array.

Specifically, the substrate 4 includes a first substrate 4-1 and a second substrate 4-2 disposed at an interval, the first substrate 4-1 and the second substrate 4-2 are disposed in parallel, two electrodes of any one of the detecting units are respectively fixed on the first substrate and the second substrate, as shown in fig. 7, the drain electrode 3 is disposed on a side of the second substrate 4-2 facing away from the first substrate 4-1, and the source electrode 2 is disposed on a side of the first substrate 4-1 facing the second substrate 4-2. Notably, NbS₃The crystal wafer 1 is cylindrical, one end of the crystal wafer penetrates through the second substrate 4-2 and forms good ohmic contact with the drain electrode 3, and the other end of the crystal wafer is fixed on the first substrate 4-1 and forms good ohmic contact with the source electrode 2. Of course, the source electrode 2 and the drain electrode 3 may also be disposed on the first substrate 4-1 and the second substrate 4-2, respectively, facing or facing away from each other. In addition, a plurality of detection circuits 11 (not shown) correspond to the detection units one by one, and read the detection units corresponding to each other respectivelyThe resulting potential difference.

Therefore, when the same or different light rays irradiate a plurality of detection units at the same time, the data of each detection unit is read, and the simultaneous proceeding of a plurality of ultra-wideband light detection processes can be realized.

Referring to fig. 8, the ultra-wideband optical detector according to the fifth embodiment of the present invention includes a plurality of the detecting units and the substrate 4, and the plurality of substrates 4 and the detecting units are in one-to-one correspondence to form an area array arrangement.

Specifically, a plurality of identical substrates 4 are provided on the same plane, and NbS is provided between the source electrode 2 and the drain electrode 3₃ Crystal slab 1, the NbS₃The crystal plate 1 is on one side of the substrate 4 and forms good ohmic contacts with the source electrode 2 and the drain electrode 3, respectively. In addition, the cross section of the source electrode 2 and the drain electrode 3 is rectangular, and both extend through the substrate 4 and extend downward to form pins, and the two pins can be inserted into the interface of the detection circuit 11 (not shown in the figure), so that the lead connection is omitted. A plurality of detection circuits 11 (not shown) correspond to the detection units one by one, and read data of the respective detection units.

Therefore, when the same or different light rays irradiate a plurality of detection units at the same time, the data of each detection unit is read, and the simultaneous proceeding of a plurality of ultra-wideband light detection processes can be realized.

By combining the above embodiments, it can be known that the detection bandwidth of the detector can be from ultraviolet coverage to terahertz waveband, and the detector has an ultra-wide detection bandwidth, and also has the advantages of high speed, sensitivity and quick response. Meanwhile, the detector is simple to prepare, low in cost and wide in prospect in practical application. In addition, although the detector in the above embodiments achieves detection through the photothermal effect, it should be understood by those skilled in the art that other detection principles including, but not limited to, the radiative thermal effect, the pyroelectric effect, etc. may be adopted in other embodiments.

In the description of the present application, the terms "mounted," "connected," "fixed," and the like are used in a broad sense, and for example, "connected" may be a fixed connection, a detachable connection, or an integral connection; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In the description herein, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.